There is no dedicated VST for Wersi instruments yet, however you could have a look for a used Wersi OX7 Midi Module, which pop up from time to time, as this is currently the closest you can get. Really it all depends on how accurate you want the emulation, (And what vintage of Wersi you wish to emulate) so it is worth giving the VST you mention a try, however I found it to be more Hammond than Wersi. (Although it is no substitute for the proper Hammond Emulators out there either)
Hope this helps
Bill
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